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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script type="text/javascript">
        0b111110111 === 503 // true
        console.log(0b111110111 === 503);
        0o767 === 503 // true
        console.log(0o767 === 503);
    </script>
</body>

</html>